Airway stenosis (or “airway narrowing”) is a medical condition that occurs when some portion of a patient's airway becomes narrowed or constricted, thus making breathing difficult. A stenosis may occur in any part of the airway, i.e. larynx, trachea, bronchi or a combination (laryngotracheal or tracheobroncial stenosis) in adults or children and due to any of several different causes. By far the most common airway stenoses (approximately 95%) are acquired, meaning the patient is not born with the condition, and the most common cause of airway stenosis is trauma caused by intubation (a tube placed in the airway for ventilation/breathing assistance in a patient who cannot breathe). Intubation for prolonged periods of time may traumatize the airway, causing scar tissue formation that forms the stenosis. Sometimes the cause of stenosis is unknown, such as in idiopathic subglottic stenosis. Managing airway stenosis is one of the most challenging problems for an ENT (ear, nose and throat) surgeon.
Subglottic stenosis is one form of airway stenosis that occurs in the larynx, below the glottis (the area of the larynx around the vocal chords). The disorder can either be congenital or acquired and can affect both adults and children. Acquired subglottic stenosis is the most commonly acquired anomaly of the larynx in children and the most common abnormality requiring tracheotomy in children younger than one year. To correct subglottic stenosis, the lumen of the cricoids area is expanded to increase airflow during breathing. Surgical correction of subglottic correction of subglottic stenosis has been performed with various techniques over the years.
Therapies for treating airway stenosis range from endoscopic treatments, such as dilation and laser resection, to open procedures such as laryngotracheal reconstruction. In one technique, a series of rigid dilators of increasing diameter are pushed down the airway, gradually expanding the constriction but also applying unwanted shear forces to the airway. More recently, balloon catheters have been used to perform airway dilation. Such a balloon procedure is described, for example, in US Patent Publication No. 2010/0168511 which is incorporated herein by reference in its entirety. The system described in that patent application is configured for use in an airway and describes a system for dilating a stenotic region with a catheter shaft having an overall length of less than 70 cm, an inflatable balloon disposed along a distal portion of the catheter shaft, and a stylet. The method for dilating a stenotic region in an airway includes advancing a balloon catheter through the airway of a patient to position an inflatable balloon of the catheter within at least a portion of the stenotic region, maintaining a position of the catheter relative to the patient and inflating the balloon to dilate the stenotic region.
Methods and devices for improved patient comfort would allow for patient ventilation during dilation of the stenotic region in the airway and increased flexibility for the physician with regard to duration of dilation and number of inflation and deflation cycles. These objectives are addressed by the embodiments described in this application.